You are more likely to crash your car by using your smartphone than by being high on cannabis or drunk on alcohol, according to new research.

The Institute of Advanced Motorists (IAM) and Transport Research Laboratory (TRL) tested drivers using a car simulator and had them use Facebook on their phones while driving.

Reaction times slowed by 38 percent and the drivers did not manage to stay in their lane.

IAM then compared its results with past studies into the effects of driving under the influence of drink or drugs.

It has been found that cannabis slows driving reaction times by 21 percent and people at the wheel of a vehicle while over the legal limit for alcohol reacted up to 15 percent slower.

The government now needs to highlight the dangers of using a smartphone while driving, IAM said.

"This research shows how incredibly dangerous using smartphones while driving is, yet unbelievably it is a relatively common practice," IAM chief executive Simon Best said.

"If you're taking your hand off the wheel to use the phone, reading the phone display and thinking about your messages, then you're simply not concentrating on driving.

"It's antisocial networking and it's more dangerous than drink-driving and it must become just as socially unacceptable."